This invention relates to an apparatus for delivering a tubular to a well centre.
During the construction of oil and gas wells a plurality of tubulars are transferred from a storage area to the well centre. Typically, each tubular is transferred to the V-slot adjacent the rig flow by a conveyor. The tubular is then lifted by an elevator and swung into position over the well centre ready for attachment to a string of tubulars extending down the well.
One of the difficulties associated with this process is that as the elevator moves the tubular, the tubular swings back and forth like a giant pendulum. This is potentially very hazardous, particularly when handling tubulars of large diameters.
An aim of at least preferred embodiments of the present invention is to reduce this problem.
According to one aspect of the present invention there is provided an apparatus for delivering a tubular to a well centre, which apparatus comprises means which, in use, inhibit swinging motion of the tubular whilst it is suspended from an elevator.
Preferably, said means comprises an arm which is pivotable between a first position and a second position.
Advantageously, said arm is provided with a stub axle which is provided with rollers for supporting said tubular.
Preferably, the apparatus further comprises a ramp which can be placed against a rig floor, and a tray which can support a tubular and be moved along said ramp.
The ramp may define an angle with the horizontal of between 30 degrees and 70 degrees, but it is normally intended to be used at angles of from 110 to 60 degrees.
In one embodiment, said arm is mounted on said ramp.
In another embodiment, said arm is mounted on said tray.
Alternatively, the arm may be mounted on the derrick.
Advantageously, said arm is rotatable about its axis to release said tubular therefrom, for example by an hydraulic motor.
Preferably, the apparatus includes an hydraulic motor to pivot said means.
According to another aspect of the present invention, there is provided an apparatus for delivering a tubular to a well centre, which apparatus comprises a ramp which can be placed against a rig floor, a tray for carrying said tubular and means which, in use, enables said tray to ascend or descend said ramp.
Preferably, said ramp further comprises a rack.
Advantageously, said means is a pinion mounted on said tray and engageable with said rack.
The means by which the tray moves along the ramp may be of any suitable means, but is preferably a rack and pinion.
Preferably, said means comprises two pinions, one mounted adjacent each end of said tray.
Advantageously, said tray further comprises a support wheel.
Preferably, said tray further comprises a pipe sledge mounted for longitudinal movement therein.
Advantageously, said tray further comprises a pipe pusher mounted such that, in use, said pipe pusher moves said tubular longitudinally within said tray.
According to another aspect of the present invention, there is provided an apparatus for delivering a tubular to a well centre, which apparatus comprises a tray for supporting said tubular, and means which, in use, can apply a force to said tubular to move it longitudinally with respect to said tray.
Preferably, said means comprises a piston and cylinder.
Advantageously, said apparatus further comprises a ramp which can be placed against a rig floor, and a tray which can be moved along said ramp.